create tapable header that will switch between bar chart and percentage

WIP - add secondary header for 7 days

closed #21

Shared/views/HeaderStatsView.swift

@@ -95,6 +95,8 @@ struct HeaderStatsView : UIViewRepresentable {
         dataSet.colors = Mood.allValues.map({ NSUIColor( $0.color ) })
         dataSet.secondaryTextColor = UIColor.systemGray
         dataSet.valueColors = [.white]
+        dataSet.highlightAlpha = 0.0
+        
         if let descriptor = UIFontDescriptor.preferredFontDescriptor(
           withTextStyle: .body).withSymbolicTraits([.traitBold]) {
             dataSet.valueFont = UIFont(descriptor: descriptor, size: 0)